or regional anesthesia. Risks of complications of the procedure includes: pyelosinus extravasation (contrast going into renal sinus) and pyelotubular (contrast going into collecting duct) reflux of contrast due to overfilling of the urinary system. It can cause pain, fever and chills. Infection may be accidentally introduced into the urinary tract. There can be also damage or perforation of renal pelvis or ureter. Rarely, acute renal failure can occur. Treatment Depending on the outcome and diagnosis following an IVP, treatment may be required for the patient. These include surgery, lithotripsy, ureteric stent insertion and radiofrequency ablation. Sometimes no treatment is necessary as stones <5mm can be passed without any intervention. Future IVP is an affordable and useful imaging modality and continues to be relevant in many parts of the world. In the developed world, however, it has increasingly been replaced by contrast computed tomography of the urinary tract (CT urography), which gives greater detail of anatomy and function. History The technique of IVP was originally developed by Leonard Rowntree of the Mayo Clinic in the 1920s. IVP was previously the test of choice for diagnosing ureter obstruction secondary to urolithiasis but in the late 1990s non-contrast computerized tomography of the abdomen and pelvis replaced it because of its increased specificity regarding etiologies of obstruction. Because of increased accuracy, computed tomography and ultrasounds of the renal tract are now used; ultrasounds additionally do not involve radiation. Etymologically, urography is contrast radiography of the urinary tract (uro- + -graphy), and pyelography is contrast radiography of the renal pelvis (pyelo- + -graphy), but in present-day standard medical usage, they are synonymous. See also Urodynamics Urology References External links eMedicine NLM/MedlinePlus RadiologyInfo: IVP Cardiovascular and Interventional Radiological Society of Europe RCR guidelines Urologic imaging Projectional radiography